I don't know Roger who answered from jp but thats what he told me . He said that wider boards would get me to plane sooner but once they planned would feel very large boards for my weight and maybe the x-cite ride 134 would be better for me. Anyway I will have the chance tomorrow of borrowing a larger fin and have some turns with a jp slalom board 82cm and an isonic 85cm so I'll tell you how it feels if you don't mind.
Thanks for the advise for the fin.

You also have to consider that of course I'm not so experienced as other guys here and have not tested so many boards so I have lots of questions